oh my gosh! if only the US had something similar for suitably qualified british people! why is everything so "one way" between our two countries?
the closest thing is the H1B visa, which is subject to very low caps which are always exhausted within 3 o4 months, ties you to a specific employer (so no job mobility and a 10 day window to leave the country after you quit or are laid off), mandates that the employer pay you above the Dept of Labor's specified average salary for that profession, costs approx $2000 (which the job seeker isn't permitted to pay - it has to come from the employer, so really difficult to move jobs), takes months to process, and doesn't grant you indefinite leave to remain even after 6 yrs. i know people who studied for 4 yrs in the US and then had a work permit for 6 years and then had 10 days to up 'n out.
1) For the HSMP Visa, there are 2 separate applications: one for individuals under 26 years of age (or 28, I forget) and another for those above that age. The points allocated in regard to experience, education, and earnings (the three main criteria for passing) are different. When I applied, there was a 6 month backlog according to the website but my application was processed in 3 weeks! Although, I am based here and had been working here for 3+ years before I applied which may have helped. It is a great thing to not have to be tied to a single employer. You have nothing to lose by applying. If, in the interim, you get approached for a job then you can notify the Home Office so they may expedite your application.
The average UK citizen gets about 25 vacation days. Some may get 20 while others may get 27 or 30. I tend to take my 25 days every year as do most others I know. If not, you get a payment at year end for unused days or can carry over (generally if only a few days) and must use them within the first 90 days of the year.
2) I've interviewed over the phone for 1st interviews even though I am based in London. Some companies elect this approach. I've interviewed over the phone for a role in Hong Kong and then made plans to meet colleagues in the London office for the next round. Same could happen with you in the US if a company is in your city. Ultimately, it depends on the policy of the company and department you are interviewing with.
When I got my job in London 4 years ago, I interviewed in NY with the US office who then inquired if I was interested in working in London. Then I met a representative from London in NY who then put me in touch with management in London, over the phone.
3) I've been in the UK for 3+ years and haven't driven once. If you drive into Zone 1, you have to pay a daily Congestion Charge. It was 5 quid but it may have increased recently. This is on top of daily parking and petrol costs (which are about $8/gallon - astronomical compared to US prices). Needless to say, taking public transportation, riding a bike, walking, or owning a scooter (avoids the congestion charge) are very popular here.
Good luck.